Automatic electric-current regulator



Jan. l8 1927.

BEST AVAILABLE COP.

- 1,615,018 w. LANGDON-DAVIES ET 1.

AUTOMATIC ELECTRIC CURRENT REGULATOR Filed May 2a. 1925 2 Sheets-Sheet 1 BEST AVAILABLE COP w. LANGDON-DAVIES ET AL wrouuvnc ELECTRIC CURRENT REGULATOR Filed May 28, 19,23 2 Sheets-Sheet?) i I l I i 0 6 ,4m/heres. d

uvven'loz' Patented Jan. 18, 1927.

UNITE'D' STATES BEST AVAILABLE COP". i

j 1,615,018 PATENT OFFICE.

'wan'rnn' .LAnenon-nAvIEsAnn iume- SOAMES, or LONDON, ENGLAND; cyan. FREDERICK 'WRIGHT, EXECUTOR 0F SAID WALTER LANGDON-DAVIES, DECEASED,

ASSIGNOB T0 SAID SOAMES.

AUTOMATIC ELECTRIC-CURRENT REGULATOR.

Application filed May 28, 1923, Serial No. 642,063, and in Great Britain June 19, 1922..

This invention relates. to automatic electric current regulators for use as choke coils inalternating current arc welding.

Inaro welding-it is preferable that the circuit shou'ldhave what is known as a drooping volt-ampere characteristic; i. e. that the volts should decrease as the. current increases.

If however the volts drop too rapidly with respect to the current, itis 'diificult to strike, or set up, the arc. is too slow, there is apt to be excessive current in the arc. j

The object of this invention is to provide an improved regulator which will automatically'give the circuit a slowly fallingvoltampere characteristic when the arc is being struck, and a more rapidly falling characteristic when the arc has been formed.

A drooping volt-ampere characteristic has hitherto been obtained by connecting an impedance, that is, either a resistance, a choke, or both,- in series with some part of the welding circuit. When a transformer is used this maybe connected either in the pri-.

mary or the-secondary circuit. When no transformer is used, or it is not convenient to alter its connections, the impedance is put in series with the arc. Such an impedance gives a fixed volt-ampere characteristic, which can only be altered by altering the value of the impedance so connected. r

The same effect, namely a--- drooping voltampere cl1aracteristic, l1as alsobeen obtained by giving a transformer a certain amount otmagnetic leakage, that is providing that all the magneticffiux set up does not pass through all the windings. and thus the windings are not all mutually inductive. This magnetic leakagehas been varied by varying the permeabilityof the magnetic leakage paths. such as filling them more or less with iron fixed in various positions- This has the same effect on the electrical circuits as varyin'g the impedance referred to.

' Again, the keeper or magnetic leakage member has in some cases been adjustable so as to vary the amount of leakage and in other cases has'bcenarranged so that it has been moved automatically onguides by the magnetic flux, its movement-being controlled say by'a spring and a dash pot. 9

An automatic current regulator according to this invention for use as a choke coil If however the volt drop ing C surrounds the keeper A 'an inductive winding acting to produce a flux 111 the magnetic CIIClllt formed by the core and its keeper, two stops to determine the initial and final relative positions of the core and the keeper so that the volt-ampere characteristic curve of the regulator lies between two definite volt-ampere characteristic curves corresponding to sald initlal and final positions, and means for varying the positions of said stops.

i The keeper or flux regulator may be pivoted or hinged but this is not necessarily the case and 1ts move1nent may be guided orconstrained in any convenient way. "What-. ever the nature oflts movement it is preferred that its construction shall be such that if desired the keeper or flux regulatormay, in its final position, close the leakage path as far as possible leaving no appre- 'ciable air gap in that path.

In the accompanying drawings. Figure 1 shows dlagrammatlcally in side I elevation one construction of automatic current regulator according to this invention,

Figure 2 is a diagram showing an alternative form, and v Figure 3 shows a volt-ampere characteristic curve such asmay be obtained by the use of, the improved regulator.

The regulator illustrated in Figure 1 comprises a U-shaped core A having a keeperor flux regulator A ,pivoted at A and provided with a controlling spring A wh ch tends to holdit in the position shown in full lines where it restsagainst a stop D whose position is adjustable in a slot D The core A*- has a. w nding B and another wind- The two windings act as parts of -a choke coil and when they are energized the keeper A will tend to move into the position shown in dot and dash lines. Its final position is determined by the stop D which is capable of fine adjustment by means of the screw D. Some such arrangement is.desirable in any construction where movement ofthe keeper;

when approaching the closed position -makes BEST AVAILABLE COP.

a comparatively large difference in the reluctance of the magnetic circuit.

Figure 2 shows another form of regulator according to this invention. In this form thekeeper A. is arc shaped and pivoted as at A so that it swings in ah arc across the curved poles of "the core A". The leading end A" of the keeper is made of gradually decreasing cross section so that the decrease in the magnetic reluctance of the circuit, as the end A approaches the adjacent pole, is

' less sudden than it would he were the keeper. of uniform cross section throughout. Thevariable stops are'indicated at D" and D and the controlling spring at F". Each stop is adjustable in the slot I). Only one wind- I ing is shown as at B but this winding may be on the keeper A or that member may carry a second winding.

Figure 3 is merely intended to show how the improved regulator acts in giving achar- -acteristic curve lying between two drooping volt-ampere-characteristics corresponding to the initial and final positions determined by the stops. The curve a may be taken for instance as that which would be givcmif the leakage member, for instance A (Figure 1), remained in its initial position against the stop D whilst the curve 6 indicates that given when the arm rests against the stop D. Thus in working, the actual volt-ampere characteristic may, as indicated by the curve a, start on the curvea and pass on to the curve b.

By shifting the stop D nearer to the stop I) the curve a would approach nearer to the curve I) and vice versa.

In Figure 3-the horizontal ordinate o (2 represents the value of the striking currentand 0 e the welding current, the vertical ordinate 0 f representing the open circuit volts and o g the welding volts.

It will be appreciated that the nature of the curves will vary according to the design of the magnetic circuit'and the arrangement and disposition of the windings. For instance the regulator might be so constructed that after a given current was reached the voltage in the working circuit would fall suddenly.

What we claim as our invention and desire to secure by Letters Patent is 1- 1. An automatic electric currentregulator for use as a'choke coil in arc welding, comprising a core of magn ctic material, a keeper or fiux regulator-adapted to more relative 1y to said core, such movement of the keeper varying with and using responsive to the magnetization of said core whereby the impdance is automatically varied with I the movement of the keeper,"an inductive winding acting to produce a flux in the magnetic circuit formed bythe core and. its kee r, two stops-to determine the initial and ti: 1 relative positions of the core and the'keeper so that the volt-amperexcharacteris'tic curve of the regulator 'lies'between two definite volt-ampere characteristic curves corresponding to said initial and final positions,

and means .fonvai'ying the-positions of-said 2. An automatic electric current regulator for pse as a chokecoil in arc welding, com: prising a coreof magnetic material, a keeper or flux regulator adapted tomove relatively to said core-suchmovement of the keepervarying with and? res onsive to. the

magnetization of said core w ereby the im- 'Pedance 1s automaticallyvaried with the movement of the keeper an inductive winding in series with the we ding arc and acting to produce aflu'xfin'the. magnetic circuit formed by the core and its keeper, two stops to determine the initial and final relative sitions of the core and .the keeper sotii the volt-ampere characteristic curve of the regulator lies between two definite volt-ampr characteristic curves corresponding to said initial and final positions, means for varying the positions-of said stops,- and means for controlling the movement of the keeper.

3. -An automatic electric current regulator for use as a choke coil in arc welding, comprising a core of magnetic material, a keeper or flux regulator adapted to move relatively to said core; such movement-of the keeper varying with and being responsive to the magnetization of said core whereby the impedance is automatically varied withthe.

movement of the keeper, an inductive windmg in series with the welding arc and acting to (produce afiux in the magnetic circuit names to this specification.

WALTER LANGDON-DAVIES. ALFRED SOAMES. 

